Question

If the sum and difference of two numbers are 20 and 8 respectively, then the difference of their square is: indiabix

Answer 1

${x}^{2} - {y}^{2} = (x + y)(x - y)$
here
$x + y = 20$
$x - y = 8$
so
${x}^{2} - {y}^{2} = (20)(8)$
${x}^{2} - {y}^{2} = 160$